package com.hmdp.service.impl;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.*;

import static com.hmdp.utils.RedisConstants.CACHE_SHOP_KEY;
import static com.hmdp.utils.RedisConstants.SHOP_GEO_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IShopService shopService;

    @Override
    public Result queryById(Long id) {
        String key = CACHE_SHOP_KEY  + id;
        //1、从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2、判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //3、存在直接返回
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return Result.ok(shop);
        }
        //4、不存在，根据id查询数据库
        Shop shop = getById(id);

        //4.1不存在，返回错误
        if(shop == null){
            return Result.fail("店铺不存在");
        }
        //4.2存在，写入redis
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop));

        //5、返回
        return Result.ok(shop);

    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要根据坐标查询
        if(x == null || y == null){
            //不需要坐标查询，按数据库查询
            Page<Shop> page = shopService.query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }
        //计算分页参数
        int from = (current - 1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = SystemConstants.DEFAULT_PAGE_SIZE;

        //查询redis、按照距离排序、分页
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end));


        //解析出id
        if(results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if(list.size() <= from) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = new ArrayList<>(list.size());
        Map<String ,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result ->{
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            distanceMap.put(shopIdStr, result.getDistance());
        });

        //根据id查询Shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for(Shop shop:shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //返回
        return Result.ok(shops);
    }
}
